This is a request for support for the Tenth International Workshop on Human Gene Mapping (HGM 10) to be held in New Haven, Connecticut, June 10-17, 1989, and a preliminary, organizing meeting of committee chairpersons to be held August 28-31, 1988, also in New Haven. The major aim of these international workshops has been the critical periodic review and updating of the extensive human gene mapping data and the compilation of a comprehensive human gene map with accompanying reports prepared by committees of experts in the appropriate areas. The continuous updating of a standard system for gene names and symbols and the clarification of mapping inconsistencies has obviated much confusion in the field. The compilation of comparative gene mapping data and the production of extremely valuable listings of the characteristics, availability, and the sources for recombinant DNA gene probes are other important objectives of these meetings. The reports from the nine prior Human Gene Mapping Workshops have been an important resource for workers in basic genetics and in human genetics, including clinical and molecular genetics, cytogenetics, oncogenetics, immunology, population genetics, and evolution. The next Workshop will play a pivotal role in summarizing the knowledge on the human gene map at the onset of a more concerted effort to fully map the human genome. A map that is as authoritative, accurate, and complete as possible is essential. The rapid rate at which data are already being collected makes it particularly critical that the information be carefully evaluated and compiled by experts in the field. The Workshop will also introduce newer methods of electronic data handling and produce a computer database, as well as the written reports, that can be widely distributed.